Reverberation time, distribution of sound pressure, intelligibility, and/or other parameters are used in sound room evaluation. But characteristics of room acoustics are complex, and often quite different impressions are received from rooms that have nearly the same parameters. These differences might come from the difference of spatial information, especially in early reflection periods. Thus a four-microphone method is proposed to measure spatial information of the room. Here, the sound field reproduction using the wavefront synthesis [A. J. Berkhout, J. Acoust. Soc. Am. 93(5) (1993) and Y. Yamasaki, J. Acoust. Soc. Jpn. 10(2) (1989)] based on the four-point measurement is discussed.